The present invention refers to a nozzle for use in a torch head of a plasma torch apparatus, comprising a nozzle body member of essentially cylindrical configuration having a central longitudinal axis, an opening running through the nozzle body member, located coaxially with the central longitudinal axis, and having an inlet end and an outlet end, and a plurality of cooling channels running through the interior of the nozzle body member and arranged symmetrically around the central longitudinal axis. Moreover, the present invention refers to a nozzle assembly for use in a torch head of a plasma torch apparatus, comprising a nozzle as referred to herein above as well as a nozzle supporting member.